The Sword of Ares was a distinctive weapon forged by Hephaestus for Ares. The weapon was the receptacle of all of Ares' powers, and whoever possessed it became God of War.
It was briefly held by Sisyphus after his escape from Tartarus, and he attempted to sell it to a group of ruthless warlords. (XWP: "Ten Little Warlords")
Ares thought that Iolaus had killed his esteemed warrior Gravus and attacked Iolaus, Hercules intervened and there was an incredible fight, they exchanged blows, Hercules dodged the sword blows and ended up breaking through the temple wall, and outside, Hercules was launched and Ares temporarily lost his sword, if not for Ares's superjump, Hercules would almost have taken his sword and soon would have become the new god of war, even if it wasn't for Hercules' pleasure to have the deity of war, but it would be a way of punish Ares by making him human and therefore impotent for a while. (HTLJ: "Stranger in a Strange World")